Latrophilin mediates insecticides susceptibility and fecundity through two carboxylesterases, esterase4 and esterase6, in Tribolium castaneum

Abstract

Latrophilin (LPH) is known as an adhesion G-protein-coupled receptor which involved in multiple physiological processes in organisms. Previous studies showed that lph not only involved the susceptibility to anticholinesterase insecticides but also affected fecundity in Tribolium castaneum. However, its regulatory mechanisms in these biological processes are still not clear. Here, we identified two potential downstream carboxylesterase (cce) genes of Tclph, esterase4 and esterase6, and further characterized their interactions with Tclph. After treatment of T. castaneum larvae with carbofuran or dichlorvos insecticides, the transcript levels of Tcest4 and Tcest6 were significantly induced from 12 to 72 h. RNAi against Tcest4 or Tcest6 led to the higher mortality compared with the controls after the insecticides treatment, suggesting that these two genes play a vital role in detoxification of insecticides in T. castaneum. Furthermore, with insecticides exposure to Tclph knockdown beetles, the expression of Tcest4 was upregulated but Tcest6 was downregulated, indicating that beetles existed a compensatory response against the insecticides. Additionally, RNAi of Tcest6 resulted in 43% reductions in female egg laying and completely inhibited egg hatching, which showed the similar phenotype as that of Tclph knockdown. These results indicated that Tclph affected fecundity by positively regulating Tcest6 expression. Our findings will provide a new insight into the molecular mechanisms of Tclph involved in physiological functions in T. castaneum.

Identification and Expression Analysis of G Protein-Coupled Receptors in the Miridae Insect Apolygus lucorum

“…The expression pattern of insects Cirl, which had been reported to be expressed in multiple tissues (103,107), was also like vertebrate Cirl-2 (108). Although there is only one Cirl member in insect species, Cirl is still involved in multiple physiological processes, which can regulate sensory, developmental, reproductive, and immune functions in insects (104,109). Here, B10 had been detected in all transcriptomic samples and its distribution range is wider than in T. castaneum and D. melanogaster (103,106).…”

Insecticidal Activity of Artemisia vulgaris Essential Oil and Transcriptome Analysis of Tribolium castaneum in Response to Oil Exposure

“…After soaking for 1 min, the treated larvae in each group were placed on filter paper and allowed to air dry for 2 min. Each group was then transferred to an 8-mL glass vial and maintained under standard conditions as previously described (Wei et al, 2019). The acetone exposure group served as the negative control group in this study.…”

Review of Insecticide Resistance and Its Underlying Mechanisms inTribolium castaneum

“…The induction of Tcest4 and Tcest6 gene expression after treatment with carbofuran or dichlorvos insecticides revealed their detoxification ability and the RNAi of Tcest4 and Tcest6 further confirmed that it had a vital role in insecticide resistance. In addition, the study suggested that lph has a vital role in regulating the activity of Tcest4 and Tcest6 [165]. All these studies revealed the detoxification ability of carboxylesterases towards toxicants and the induction characteristics of some carboxylesterases could be used as biomarkers to assess the resistance against certain xenobiotics.…”

“…This resistance mechanism allows insects to overproduce the enzymes mainly cytochrome P450 monooxygenases (CYP450s), carboxylesterases (CarEs), and glutathione S transferases (GSTs), to thwart the toxic effects of insecticides. This advantage helps to evolve resistance in T. castaneum Insecticides populations for all main classes of insecticides currently used for stored product pest control such as organophosphates, carbamates, and pyrethroids [163][164][165]. The comprehensive genomic and transcriptomic analysis has led to the identification of the key genes encoding detoxifying enzymes such as CYP450s, GSTs, and CarEs.…”

“…It is interesting to observe that T. castaneum used two genetic strategies to adapt to these insecticides attack 1) a pool of Laccase2 enzyme ensured the protection by synthesizing the thicker cuticle which prevented the entry of insecticide into the insect body 2) a pool of esterases and lipases contributed the protection by hydrolysing or sequestering which rendered the insecticides ineffective [208]. Similarly, the functional role of two carboxylesterase genes of T. castaneum (Tcest4 or Tcest6) were investigated by RNAi and identified their interaction with Latrophilin [165]. Latrophilin (lph) is an adhesion G-proteincoupled receptor that is essentially involved in the physiological process and cellular detoxification process although one member of lph existed in T. castaneum [209,210].…”